Self-contained hydraulic servo mechanism



Jan. 11, 1949. 4 E A, RCKWELL 2,458,736

suiv-CONTAINED HYDRAULIC sERvo MECHANISM Filed June 29, 41945 v 9 Sheets-Sheet 3 INVEN-roR Zw/Aeon. @exa/fc4 Jan. ll, 1949. E. A. RocKwELL 2,458,736

SELF-CONTAINED HYDRAULIC sERvo MEcHAnIsu Filed June 29, 1943 9 Sheets-Sheet 4 VENTOR ATTORNEY Jan. 11, 1949.

E. R'OCKWELL SELF-CONTAINED HYDRAULIC SERVO MECHANISII 9 Shasta-sheet 5 Filed June 29,. 1945 INVENTOR WW/*f90 A. @cnn/ELL ATTORN Y l1, 1949. E. A; RocKwELl.

SELF-CONTAINED HYDRAULIC SERVO MECHANISM 9 Sheets-Sheet 6 Filed June 29. 1943 llllll lll EN EN vWN mm INVENTOR ,e0/1. ,GbcKn/ELL Ibm L ATToRN Y E.v A. RocKwELL SELF-CONTAINED HYDRAULIC SERVO IIECHANISH Jan. 11, 1,949.

9 Sheets-Sheet 7 Filed June 29, 1943 l [N Z4 vENToR i PW/'192A Rockwezl. fag BY I ATTORY E. A. RocKwELl-A SELF-CONTAINED HYDRAULIC SERVO MECIIANISM` Jan. l1, 1949.

Filed June 29, 1943 9 Sheets-Shee-t 8 Painted 1.11.11, 1949 SELF-CONTAIN ED HYDRAULIC SERVO MECHANI Edward A. Rockwell, Cleveland, Ohio Application vJune 29, 1943, Serial No. 492,745 l My invention relates particularly to a selfcontained power operated servo mechanism for controlling any device requiring a relatively large amount of work to move the same. Also, it is especially adapted for use where small followthrough manual operating input forces are required either by mechanical connections to the input or by other connections thereto, such for example as in the control of automotive vehicles, airplanes, steam engines, steering gears or loco--V motive reverse gears.

The object of my invention is particularly to provide a power-driven apparatus of the labove character, for controlling any desired device. One of the objects is to provide a hydraulic power operated mechanism which is positive, certain and accurate in operation and which eliminates the disadvantages in previous valve-operating devices. A further object is to provide a powerdriven valve-operating mechanism which operates eiectively upon the principle of hydraulic pressure and volume displacement between the control mechanism and the output power members. For this purpose, furthermore, I may utilize, also, a self-latching construction which has fast and accurate metering characteristics. Also, one-way check valves may be used in the high pressure lines leadingl to the valves to prevent reverslbility in the output members. Furthermore, I have found it advantageous to utilize hydraulic pressures obtained from a manually operated master cylinder to maintain the coordination of travel between the input means and the output means. The results obtained are iacilitated by the very slight travel of the valves, whichassists in' providing accurate increments oi' `fluid for the control of the output means. This arrangement makes it feasible to provide an efficient hydraulic remote control whereby an accurate control may be readily obtained. Also, the master cylinders used are provided with suitable liquid compensation in order to maintain the phase relation between the control means and the output means. Still another object is to provide a remotely controlled power unit for controlling or operating mechanisms in which the power unit is a compact self-contained power unit.

In accordance ywith my invention, with the high hydraulic pressures available, cylinders of relatively small displacement can be used for controlling the output. These can be most conveniently mounted upon a box section housing and opposed to each other. Pistons are connected by pushrods to an output shaft trunnioned in 16 Claims. (Cl. .6U-52) the housing. The pivot of the crank shaft and output lever can be located at the same point that the lifting or tumbling shaft is located, and the whole unit mounted together. Monitor or travel control cylinders and pistons are mounted on either side below the output shaft, and adapted to rest removably against a pin xed on an extension of the crank attached to said shaft. Control master cylinders, in one form, are located below the monitor and are preferably bored in the same casting. The pistons are positively connected by links to an independent crank journaled in the housing and having a control lever positioned on theoutside of the box for convenient attachment to the reach rod or other control. The interior of the bor acts as a supply reservoir for the oil in which the gear pump and cylinder openings are submerffed, so as to receive the rel turn now from the valves. The plmip is mounted on a bracket extending down from the cover plate to which the air motor is also secured. The valves and pressure controller are also mounted on the cover plate together with tube cceetion from the pump outlet, making a complete sub-assembly, so that these parts can be conveniently removed from the box. Externat pipe connections are made from each master-monitor outlet to the respective valve cylinder outlet. Air bleeders are provided at the high point 4of .these connections. Preferably check valves are` placed in the lines leading from the pump and the controller to each of the valves to maize the action irreversible. Lines also connect with outlets from these valves to the respective power cylinders. Air bleedersy are provided at the top of these cylinders to initially exclude all air and to allow for the initial cycling o the unit.

Further objects of my invention will appear from the detailed description of the same hereinafter.

While my invention is capable ci being carried out in many dierent ways for the purpose oi illustration I have shown only certain embodiments of my invention in the accompanying drawings, in which Fig. i is a diagrammatic side elevation of a locomotive reverse gear controlling mechanism operated in accordance with my invention;

Fig. 2 is a longitudinal vertical section of the valves and operating cylinders used therein;

Fig. 3 is an end elevation, partly in section, of

the same; v

Fig. d is a transverse'section of the same taken on line ei--t of Fis. 2;

Fig. 5 is a diagrammatic side elevation of a modified form of my invention;

Fig. 6* is a diagrammatic rear elevation of the same;

Fig. '7 is a longitudinal section of a power cylinder and attached parts in the form or my invention shown in Fig. 5;

Fig. 8 is a transverse section thereof taken. on line 8-8 of Fig. 9:

Fig. 9 is a plan view. partly in section, of the same;

Fig. 10 is a longitudinal section showing the use of a hydraulic latch in a further modiied form of my invention;

Fig. 11 is a transverse section of the modication shown in Fig. 7;

Fig. 12 is a plan view of the scale indicator shown in Fig. 5; and

Fig. 13 is a vertical section of a check valve on the high pressure inlet to .one of the modulator valves.

Referring iirst to the form ci my invention shown in Figs. 1 to 4, I have shown in a steam locomotive cab I a hand operated lever 2 carried by a pivot 3 on a bracket 4 attached to said cab. Said bracket 4, furthermore, has attached thereto a segmental rack 5 to cooperate with a sliding catch 6 mounted on the lever 2, to which there is attached a rod 1 passing through a projection 8 on a lever 2 and connected to a bifurcated hand operating lever 9 having a pivot I0 on said hand lever 2. A spring around the rod 1 and located beneath the projection 6 normally keeps the catch 6 in engagement with any one of the notches of I the rack 5. Attached to the lower end of the hand lever 2 there is a link or reach rod I2 which is pivoted to the upper end of a manually operated lever I3 having a split end I4 adapted to be tightened in place by a screw I5 on a splined end |6 of a master cylinder operating shaft I1 which passes through a gland nut I8 having a packing I9 carried by a large assembly bushing 20 screw-threaded into a cylinder housing 2| having a supporting flange 22 for attaching the same by screws 23 to any desired part of the locomotive. The inner end of the master cylinder shaft |1 has thereon a crank 24 provided with a'. lateral crank pin 25 so as to be received in a recess 26 in a link 21 having pivots 28 and 29 connected to master cylinder pistons and3|, respectively, carried in master cylinders 32 and 33 in master cylinder blocks 34 and 35, respectively. The cylinder blocks 34 and 35 are attached to the side of the cylinder casing 2| in any desired manner. As the two master cylinders are constructed in the same way only one thereof will be described. The master cylinder plunger 30 has around its periphery an annular chamber 36 which communicates by a port 31 with a passageway 38 in the cylinder block 34 and which leads to a central chamber 39 in the cylinder casing 2| for liquid compensation of the cylinder 32, the port 31 being uncovered at the end of the path of the pistonV in the cylinder 32. The annular chamber has a hole closed by a plug 39a to enable the port 31 to be drilled. A rubber U-shaped seal 40 is pro vided on the piston 30 to the right of a flange 4| on the end of said piston. Also, the cylinder 32 has a screw c'ap 42.

The cylinders 32 and 33 have discharge ports 43 and 44 which lead, respectively, to travel control cylinders 45 and 46, closed by screw caps 41 and 48, and which have therein travel control plungers 49 and 50, referred tc again hereinafter, each of the plungers 49 and 50 having a recess 50a for a plunger return spring 5012. These two travel control plungers have U-shaped rubber seals 5I and 52 adjacent to ange heads 53 and 56 thereon. The hydraulic liquid discharged under manual pressure from the chamber 32 and 33,. respectively, after reaching the cylinders 45 and 46, is delivered by pipes 55 and 56 to inlet ports 51 and 68 in valve cylinder heads 59 and 60, respectively, having air bleeder screws 6| and 62. The cylinder heads 59 and 60 are located, respectively, on valve cylinders 63 and 54 Joined together with a packing 65 and fastened in any desired way on the top of a pair of plates 65d on top of thecylinder housing 2|. The cylinder heads 59 and 60, furthermore, have within the same, respectively, chambers 66 and 61 having therein plungers 68 and |59 provided with U-shaped seals 10 and 1i. The said plungers 68 and 69, also, have thereon heads 12 and 1li which provide valve seats 15 and 15 for cooperating with tubular valves 16 and 11 provided with annular valve elements 18 and "i9 cooperating with the valve seats 14 and 15. The valve 1 4, 18 acts as a discharge valve communicating with a discharge port in the valve cylindei 63 communicating with corresponding ports in the plates 65a and cover plate 80a and which in turn communicates with the chamber 39 in the cylinder housing 2| through the cover plate 65a on the housing 2 I. Similarly the valve 15, 19 communicates with a similar port 8| cornmunicating with said chamber 39. The tubular valve members 16 and 11 are constructed just `alike and only one thereof will be described in detail accordingly. The tubular valve 16 has an .annular seal 82 and a peripheral valve-balancing chamber 83 communicating with an inlet port 84 connected to a high pressure hydraulic liquid inlet pipe 85 provided with a check valve 86. A branch high pressure hydraulic liquid inlet pipe 81, having a check valve 81a, leads to a similar inlet 88 on the valve cylinder 64. The said tubular valve 16, furthermore, has a conical inlet valve 89 cooperating with a valve seat 90 on the inside of the valve cylinder 63. Also, said tubular valve 16 has a plurality of radial apertures 9| connecting with a cylindrical chamber 92 in the tubular valve 15 and with a chamber 93 on the outside of the tubular valve 16 which leads to a port 94 for supplying the modulated high pressure liquid 'which passes through the valve 90, 89 to a pipe 95 and thence to an inlet port 96 on a power cylinder 91. Similarly, the valve cylinder 64 has a delivery outlet aperture 98 for the liquid delivered by the valve 11 which is thence conveyed by a pipe 99 to an inlet opening |00 on a power cylinder |0|. The tubular valve 18, furthermore, has an annular seal |02 within a sleeve |03. Also, between the inner ends of the tubular valves' 16 and 11, which are individually self-lapping, there is a coil spring |04 for pressing the conical valves 89 against their'seats 90. The spring |04 is 1ocated in a chamber |05 which communicates by a port |06 in the sleeve |03 and a passageway |01 with the chamber 39. The passageway |01 serves as a breather opening. An internal spring |08 between pistons |09 and ||0, located within the tubular valves 15 and 11, serves, by means of piston rods I and ||2 on said pistons |09 and ||0 and attached to the heads 12 and 13 respectively, to unseat the valves 14 `fand 15 normally. Also, it will be noted that the pistons |09 and ||0 and the attached plunger heads 12 and 13 serve to balance the release valves 14, 18 and 15, 19. Rubber seals I3 and |4 are located on the piston rods and H2,

The power cylinders 91 and ||l| are provided with screw caps IIB and H4. Pistons ||1 and ||8 and piston rods I9 and |28 are yconnected to a pivot |2| on a lever arm |22, which is in the form of a yoke carrying said pivot |2|. The lever arm |22, furthermore, is carried upon a splined shaft |24 having a locking screw |25. The shaft |24 is carried within bushings |28 and |21 in the cylinder housing 2| and a packing |28 is located adjacent to the bushing |21 and held in place by a gland nut |29. Furthermore, the lever |22 has a downwardly directed bifurcated end |80 provided with a cross `pin |3| which is located between the inner ends of the two travel control plungers B9 and 58.

On the outer end of the shaft |24 there is a lever arm |32 fastened in place with a washer |33 and a nut |34. The lower end of the lever arm |32 is pivoted to a yoke |35 of a locomotive reverse gear such as is shown, for example, in Fig. 5, and for operating any desired type oi locomotive reverse gear, such as is shown in Marks. Mechanical Engineers Handbook, first edition, 1916, pages 975 and 977, published by McGraw-Hill Book Co. Inc., New York.

The high pressure liquid supplied by the pipe 85 to the tubular valve 19, ll is delivered from a gear pump |36 of any desired type, mounted on a bracket |9641 (Fig. 2) on the cover plate ddd so as to receive liquid from the chamber d@ by the usual inlet opening, which is driven by a shaft i3?, which shaft in turn is driven by an air vane or other motor |99, as shown in Fig, l.. However, it may be an electric motor, as shown in my Patent No. 2,292,546, upon Snap action apparatus. The motor wil, which is fastened to the cover plate 65a, may be driven by compressed Y air received through an opening |99 from a pipe Mii which leads to a tting if-li on the top of a pressure accumulator casing |52, also fastened to the cover plate 65a, having a vent and drain passageway |52@ leading to chamber 39 and a compressed air inlet opening M33. The supply of compressed air to the pipe @|59 is controlled by a valve plunger ili having a conical valve member idd cooperating with a valve seat idd on the interior of the fitting Mii. The valve ia, it@ is normally unseated. For this purpose, the valve plunger |135 has a longitudinal passageway to receive a bolt lill, on one end oi which there is a head ist* adjacent to an annular spacing plunger |99 to hold in place a rubber seal idd. The other end of 'the bolt Mill passes through a seal idi and a spacing member |52 and thence through a washer isla and a split retainer ring |53 and a washer |53a in the fitting Mii against the lower face of which there is provided a coil spring |563 held in place by a washer |55 and a nut |59. The supply of compressed air from the inlet M43 to the port itil is adapted to be cut oi' automatically when there is a suiicient accumulation of pressure in the hydraulic liquid in the system so as to interrupt the operation of the gear pump |36. For this purpose, the pipe 35 has a branch pipe |51 which leads by a fitting |59 to a passageway |59 in a base block |69 to which the accumulator casing |42 is secured. The passageway |59 leads to a plunger chamber lili, having a port i6|a leading to the pipe 8l and having a plunger |62 therein provided with an annular seal |63. The plunger |62 operates against a screw head |95 which ls located over a snap action screw |65 where it is held in place by a nut |96 so as to support a dished plate |91 having a series of openings |68 in a flange |69 thereon which supports a plurality of coil springs |10 around tubes |1| within the holes |88. The tubes |1| receive through the same locking bolts |12 which hold the casing |62 against the block |88 by being screw-threaded into said block and having their ends provided with nuts |13 and |14 so as, also, to hold the fitting |4| on the casing |42. At their upper ends the coil springs |10 are retained in place` by washers |15 on the rods |12 and adjacent to said washers |15, nuts |13 and |11 hold in place .a spider |18. The said spider |18 has a central aperture |19 adjacent to which thereare a plurality of pivoted arms |80, carried on pivots 8| andpressed inwardly by springs |32. The lower ends of the arms have pivoted therein rollers |83 to bear on the outside of a tubular member |84 having secured thereto a peripheral ange |85 located on a snap action block |85. Within the tubular member |84 there is a spring retainer sleeve |97 carrying within the same a coil spring |89 located on the outside of a sleeve |99. The sleeve |99 is located on a snap action rod |6911 which at this end has a head |99 adjacent to a washer |9|. The rod |8911 is arranged to slide within the snap action block |86 and beneath said block the rod |994; carries a spring retainer sleeve |92 within which there is a coil spring |93 located over a sleeve |9|l on the rod |39@ Adjacent to the sleeve i 9d, at its lower end, there is provided a washer |95 and the ,rod ttdd is arranged to hold the washer |9 in place by the rod Edda being fastened by a tongue |96 and a groove |977 and a cross pin |99 to the snap action screw |65. This snap action is shown in detail in my U. S. Patent No. 2,292,546, above referred to.

In the modified form of my invention shown in Figs. 5 to 9 and l2, l have provided a handoperated lever |99 carried on a shaft Edd passing into a casing 2|l| mounted on a bracket 292 in a cab 293 of a steam locomotive 2M, On the top of the casing adi, which has a vented lling cap 29de, there is fastened a bracket i295, by means of screws which carries, on the top of an inclined ange 2G71' thereon, an inclined indicator plate 295 having calibrations dit@ which are sub stantially eduidistant, except that there are more subdivisions in the forward drive than. in the rearward drive. The hand lever |99 passes through a slot 2|@ in the indicator plate 29d and has loosely supported around the hand lever |99 a pointer plate dii which slides along the indicator plate |293 as the hand lever |99 is shifted. The said shaft 29d, furthermore, carries a lever il i 2 which operates in a slot 2 3 lbetween two inaster cylinder pistons 2id and 2id located in master cylinders 2|@ and 21H, respectively, which are attached to the casing 2M by screws dit. These master cylinder pistons 2id and 2id may be constructed the same as the master cylinder piston 39 and 3| previously described. Pipes 2|9 and 229 lead from the ends of the master cylinders ZIB and 2H to the ends of travel control cylinders 22| and 222 having travel control pistons 223 and 229 constructed like the travel control pistons t9 and 5U. From the travel control cylinders 22| and 222 pipes 225 and 22S convey the liquid, which is received from the master cylinders 2id and 2|?, to the outer ends of plunger housings 22| and 22d attached to valve casings 229 and 299 which are constructed the same and with the same parts therein as in the case of the valve casings t3 and 66|. The high pressure liquid for the valve casings 229 and 23D is supplied thereto through pipes 23| and 232, which Maase are connected together, having a feed pipe 233 connected to a gear pump 294 constructed the same as the gear pump 36 previously described. The said gear pump 236, however, is mounted on a cover plate 234a and has an inlet pipe 296 leading to the bottom 4of a cylinder housing 236 to which the travel control cylinders 220 and 222 and the valve casings 229 and 230 are attached and within which the gear pump 29d is located. One of the gears of the gear pump 235 is carried on a shaft 231 having a bearing 28d and the said shaft 231 is driven by .a pneumatic vane'motor, mounted on the cover plate 239er. by means of a gear 239 of any desired character, said pneu matic motor, like the motor |39, being located in a chamber 240 which hasa compressed air pipe 24| for driving said pneumatic motor, leading into the same from a fitting 242, having an inlet 243 to receive the compressed air. The fitting 242 is mounted on an accumulator 24d which is constructed the same as the accumulator i452 previously described, and which is mounted on the cover plate 2341i. This accumulator 244 receives compressed air by an opening 235.

Delivery pipes 246 and 241, for delivery of high pressure liquid, are connected to the valve casings 229 and 230 so as to supply the said liquid to power cylinders 248 and 249, respectively, which are constructed the same as the power cylinders 91 and |0| previously described, The said power cylinders are attached to the cylinder housing 236, the same being provided with holes 250 for attachment by screws to any suitable part of ar locomotive. The cylinders 248 and 249 carry pistons 25| and252 connected by piston rods 253 and 254 to a pivot pin 255 of a bifurcated crank arm 256 splined on a shaft 251 carried by the casing 236. Integral with the crank arm 256 there is a subsidiary crank 250 having a laterally directed pin 259 which is located between the inner ends of the two travel control pistons 223 and 224. which is supported within the cylinder casing 236 by a bushing 260 and a ball-bearing 26| fastened in place by a cap 262 and screws 263 provided with a split locking ring 264 and a packing 265, there is splined a lever arm 266 held in place by a nut 261 and washers 268 and 269. The lever 266 carries on its outer end, by means of a pivot 210, a link or reach rod 21|. The link 21| is pivotally connected to a bell crank lever 212 of aY On the outer end of the shaft 251,v

locomotive reverse gearA carried on a fixed pivot or lifting shaft 213. The bell crank lever 212 has a lower arm 214 having a pivotal connection 215 to a lifting link 216 which has a pivotal connec tion 211 to a radius rod 218 of said locomotive reverse gear and which may be, for example, any of the locomotive reverse gears referred to in Marks, Mechanical Engineers Handbook, above referred to.

embodiment shown in Figs. 5 to 9. The form of my invention in Figs. 10 and 11 is shown mainly to illustrate a form of hydraulic latch or locking mechanism for maintaining the hand lever |99 and radius rod 218 in any desired adjusted position. In this instance, the shaft 200 is provided Within the casing 20| with a bifurcated crank 219, two arms 280 and 28| of which are provided With slots 282 and 283 to receive sliding square blocks 284 and 281 on a bolt 285 having a. nut 286 thereon. The blocks 284 and 281 slide in the recesses 282 and 283, respectively, and between the two arms 280 and 28| there is a yoke member 288,

In the form of my invention shown in Figs. `10 and 11, I have illustrated a modification 'of the through which the bolt or cross pin 286 passes. which extends into slots 289 and 290 on lunastary cylinder pistons 29l and 292 constructed like the master cylinder pistons previously described. 1n this instance the pistons 2m and 292 are located in cylinder blocks 293 and299 having screw caps 296 and 296. The cylinder blocks 299 and 29 also contain within the same hydraulic latch cylinders 291 and 298, both of which are constructed alike and only one of which, therefore, will be described in detail. Each of these cylinders contains within the same a bushing 299 provided with an inlet passageway 300 connecting with a chamber 3m, adjacent to longitudinal ports 302, communicating with a U-shaped sealing ring 308 held in place by'a retaining ring 304 which abuts against a shoulder 305 in the cylinder 291, which in turn leads into an annular chamber 306 forming a part of the hydraulic latch chamber 291, leading to an air bleeder port 301 normally closed by an air bleeder screw 308 of the usual construction. Within the bushing 299 there is a sleeve plunger 309 provided at one end with a screw cap dit. Adjacent to the screw cap 3|0 there are radial ports 3H in the sleeve plunger 399, Also, said sleeve plunger has radial ports 3|2 within the cylinder casing 20| and it will be noted that the said sleeve plunger 309 extends, likewise, into the cylinder 298, the portion within the cylinder 298 being constructed the same as the portion thereof Within the cylinder 291. A screw 3|3 passes through the yoke 298 into the sleeve plunger 309 to hold it in fixed relation in regard thereto. Also, within each of the sleeve plungers 399 there is a valve operating rod 3|4 which contacts with the cross pin 285 and at its other end has flutings 3|5 adjacent to a conical valve seat 3|6 on the inside of the sleeve plunger 309. A valve head 3 I 1 is adapted to seat on the conical valve seat 3|6, the valve head being located in a valve chamber 3|8 adjacent to the screw cap 3|0, which has a hollow stem 3I9 to receive a valve stem 320 which is integral with the valve head 3I1. A shoulder 32| on the valve stem 320 is provided for supporting a coil spring 322 located around the hollow stem 3 I 9 so that the left end of said spring 322 seats against the screw cap 3I0. As shown in Fig. 10, the yoke 288 and the sleeve plunger 309 have a lateral elongated hole 323 through which the bolt 285 passes, so as to provide a slight lost motion between the movement of the yoke 219 and the sleeve plunger 309 sopthat when the yoke 219 is moved to the left or right, in Fig. 10, it will first move the valve operating rod 3|4 to unseat .the particular valve 3|1 before the sleeve plunger 309 is moved in the corresponding direction in said gure. Without such previous movement of the valve rod 3|4 being possible, the movement of the master cylinder plunger 29| towards the left or right in said figure would not unseat the particular valve 3I1, so that the liquid in the latch chamber 291 would be trapped therein to prevent the movement of the valve plunger 309 as well as the master cylinder piston 29| to which it is attached until the hand lever |99 has been moved previously. In this way, the hydraulic latch cylinders 291 and 298 and their pistons will hold the master cylinder pistons 290 and 29| in any adjusted position, thus maintaining the adjusted'position of the hand lever 299 until said hand lever is again moved for the adjustment of the position of the locomotive reverse gear. During any withdrawalV movement of the sleeve plunger 309 from its particular cylinder the liquid will enter from the casing 20| through the passageway 300, past the seal 303, through chamber 305 and into the annular chamber 308 to the hydraulic latch cylinder 291.

. 2 to the right the link or reach rod |2 is moved to the left together with the lever I3; This moves the crank 24 to the right, in Fig. 2, thereby mov- :lng the master cylinder piston 3| to the right and simultaneously' delivering the liquid under manual pressure by the pipe 58 to the linterior of the .plunger cylinder 31 while at the same time withdrawing the liquid from theplunger cylinder 58 to the pipe 55. Accordingly, the valve 15, 13 will become seated. thereby unseating the pressure liquid inlet on the tubular valve member 11 and admitting the pressure vliquid fpast this inlet, whence it is delivered by the pipe 99 to the interior of the power cylinder' I0| so as to move the piston ||8 therein to the right, in Fig. 2, while simultaneously moving the piston I |1 in the other v power cylinder 91 to the right in said ligure. The

' discharge from the power cylinder |0| is accomplished by the unseating of the valve 15, 19 and the discharge of the liquid by the pori'| 9| to the interior of the casing 2|. This movement of the power pistons ||1 and H8 resu'ts in moving the crank |22 to the right, in Fig. 2, and thereby the shaft |24 so as to move to the left'the arm |30 with the travel controll pistons 49 and 50 as well as the arm |32. The movement oi the arm |32 transmits the motion to the link |35 and thence to the reverse gear of the locomotive vso as to. shift the radius rod, such as, `for example, the radius rod 218 shown in Fig. 5, in the usual way in operating the locomotive reverse gear. At the same time that the power pistons ||1 and ||8 are moved, as above referred to, the shaft |24, by

' means of the arm |30, will move the travel control pistons 49 and 50 so that the travel ofthe rod |35 in either direction will be coordinated to the travel of the master pistons and 3| and, therefore, also to the travel of the manual lever 2 in either direction. It will be understood that the movement of the hand lever 2 towards the lei't,I in Fig. 1, will bring about the reverse series of operations of the parts referred to, in order to drive the locomotivev rearwardly. In the operation of the said parts the high pressure liquid is provided to supply the ports 84 and ,88 in the valve cylinders, by thecompressed air which enters the inlet port |43 past the valve |44, |45and thence to the air motor |38 which drives the pump gear shaft |31 so as to deliver the high pressure liquid through the pipe 85 for supply to the valve inlet ports 84 and 88. This pressure supply is maintained at a given level of pressure by the pressure accumulator |42 in which the piston |62 accumulates the pressure received from the gear pump by the yielding of the coil springs |10 to such a point that'when the desired pressure to be maintained is reached the snap action apparatus in the said accumulator causes the interrupted surface or annular flange |85 to suddenly pass by the rollers |83 s`o that the end of the sleeve |84 contacts with the plug |55 to close the valve |45, |48, and keep the same closed until the release of the pressure on the base of the piston |62 causes the springs |10 to move the interrupted surface or annular ring |85 back below the rollers I 83by a sudden snap action. Thesnap action produces a positive and quick opening .or closing of the valve |45, 148. thus aiding and maintainingat all times the desired pressure inthe supply' of high pressure liquid. i

It will be noted, furthermore, that the chamber 38, in which the pump |38 is located for withdrawal of liquid therefromuis arranged to receive any leakages or discharge of fluid from the 'adjacent ends of the cylinders 32, 33, 45, 43, -91,

the locomotive so as to avoid any loss or inaccuracy of movement due to lag between the cab and the master cylinder pistons 2|4, 2|5. Furthermore. the power unit and control can bemounted irrespective of alignment of shafts with respect to each other. Also, in the cab there is provided anv accurate indicating scale 208 which is inclined in a position to provide an effective gradation of readings throughout the forward drive and the rearward drive of the locomotive. 4 With this arrangement of the calibrations on the inclined scale the latter can be more readily seen. Also, in this form of my invention the gear pump 234 is located adjacent to the air motor 239 so as to make the assembly more compact,

The form of my invention as shown in Figs. 10 and 1l, operates in a similar manner to the form of my invention shown in Figs. 5 to 9. However, in this instance I have provided means for maintaining the adjusted position of the manual operating lever |99 with the aid of a hydraulic latching or locking device which is comprised of the two latching cylinders 291 and 298, having therein the sleeve plunger 309 carrying the two valves 3|6 and 3|1 at the two ends of the said plunger 309 and the two vave operating rods 3|4 on either side of thev manually operable bolt 285.

The sleeve plunger 309 moves with the yoke 288 and with the master cylinder piungers 290 and 29| so that the pressure of the liquid exerted on the said master cylinder pistons cannot result, of itself, in displacing the said master cylinder pistons, nor in displacing the adjusted position of the radius rod 218 until the hand lever |99 is moved first manually. Owing to the elongated hole 328 the'hand lever 2 first moves one or the other of the valve operating rods 3 4 to unseat the valve 3| 5, 3|1 so as to release the liquid past said valve through ports 3|2 to the casing 20|. When the liquid in the other one of the cylinders 291, 298 is being drawn into its particular cylinder, this is accomplished by the entry of the liquid through the particularpassageway 300 past the rubber seal 303 and thence into the hydraulic latch chamber. By this means the locomotive reverse gear cannot be accidentally moved out of adlustmentby the forces exerted thereon unless the hand lever |99 is moved first to a new position of adjustment. v

,While I have described my invention above in detail I wish it to be understood that many changes may be made therein without departing from the spirit of the same.

I claim:

1. In combination, a' self-contained compact power'unit` and a hydraulic master cylinder controlling means therefor, said unit comprising a hydraulic power 'creating device with an inlet,

4 a hydraulic piston motor, comprising cylinders and opposed pistons therein, operated by said hydraulic power and onnected to a device to be moved thereby, a modulating valve means, uid actuated valve operating means connected to the valve means. passage means connecting theA valve operating means to the master cylinder controlling means for controlling the application of said hydraulic power to the motor, cylinders connected to said passages and in hydraulic communication with said inlet, at least at times, of said power creating device and opposed pistons therein connected to the said iirst mentioned pistons to move coordinately to the motor pistons and adapted to coordinate the travel of said controlling means and the device to be moved, and a casing into which all said cylinders open.

2. In combination, a self-contained compact power unit and a master cylinder controlling means therefor, said unit comprising a hydraulic power creating device with an inlet, a hydraulic motor, comprising cylinders and opposed pistons therein, operated by said hydraulic power and connected to a device to be moved thereby in both directions of operation, a valve means, iiuid actuated valve operating means connected tothe valve means, passage means connecting the valve y l2 l said hydraulic motor lbeing operated by said hydraulic power and connected vtoa device4 to be moved thereby in both directions of operation, a

valve means, fluid `actuated valve operating means connected to the valve means, passage means connecting the valve operating means to the master operating means to the master cylinder controll ling means, said valve means comprising a valve device for controlling the movement of the motor in each direction of operation, for controlling the application of said hydraulic power to the motor, cylinders connected to said passages and in hydraulic communication with said inlet, at least at times, of said power creating device and opposed pistons therein connected to the said first mentioned pistons to move coordinately to the motor pistons and adapted to coordinate the travel of said controlling means and the device to be moved in Aboth directions of movement, and a casing into which all said cylinders open.

3. In combinationfa self-contained compact power unit and a hydraulic master cylinder controlling means therefor, said unit comprising a hydraulic power `creating device with an inlet. a hydraulic piston motor, comprising cylinders and opposed pistons therein, operated by said hydraulic power and connected to a device to -be moved thereby in both directions of operation, a modulating valve means, fluid actuated valve operating means connected to the valve means, passage means connecting the valve operating means t0 the master cylinder controlling means, said valve operating means comprising pistons and cylinders therefor, for controlling the movement of the motor in each direction of operation, for controlling the application of said hydraulic power to the motor, cylinders connected to said passages and in hydraulic communication with said inlet, at least at times, of said power creating device and opposed pistons therein connected to the said first mentioned pistons to move coordinately to the motor pistons and adapted to coordinate the travel of said controlling means and the device to be moved in both directions of movement, and a casing into which all said cylinders open.

4. In combination, a self-contained compact power unit and a master cylinder controlling means therefor, said unit comprising a hydraulic power creating device with an inlet, having a hydraulic piston motor, comprising opposed cylinders and pistons,.an accumulator and snap action device in the accumulator for starting and stopping the supply of power to the accumulator,

prising a valve device for controlling the movement of the-motor in each direction of operation, for controlling the application of said hydraulic power to the motor, cylinders connected to said passages and in hydraulic communication with said inlet,-at least at times, of said power creating device and opposed pistons therein `connected to the said first mentioned pistons to move coordinately to the motor pistons and adapted to coordinate the travel of said controlling means and the device to be moved in both directions ofy movement, and a casing into which said cylinders open and in which casing each pair of opposed pistons are connected together, said accumulator having a drain passage leading to said casing.

5. In combination, a self-contained compact power unit and a hydraulic master cylinder controlling means therefor, said unit comprising a hydraulic power creating device with an inlet,

having an accumulator and snap action device in 1 the accumulator for starting and stopping the supply of power to theI accumulator, a hydraulic piston motor, comprising cylinders and opposed pistons therein, operated by said hydraulic power and connected to a device to be moved thereby in both directions of operation, a modulating valve means, fluid actuated valve operating means connected to the valve means, passage means connecting the valve operating means to the master cylindercontrolling means, said valve operating means comprising valve pistons and cylinders therefor, for controlling the movement of the motor in each direction of operation, for controlling the application of said hydraulic power to the motor, cylinders connected to said passages and in hydraulic communication with said inlet, at least at times, of said power creating device and opposed pistons therein connected to the said first mentioned pistons to move coordinately to the motor pistons and adapted ,to coordinate the4 travel of said controlling means and the device to be moved in both directions of movement, and a casing into which all said cylinders open and in which casing each pair of opposed pistons are connected'together, said accumulator having a drain passage leading to said casing and said valve having a discharge passage to said casing.

6. In combination, a device to be moved, manual means for controlling the position of the same, a master cylinder operated by the manual means, a modulating valve adapted to control the delivery of pressure liquid from the valve, power cylinders and opposed pistons therein operated by said pressure liquid, a casing having a chamber between said power cylinders and on which casing v the powercylinders are mounted, said power pistons being connected to said device, and a pump in said chamber having a pressure accumulator connected thereto for supplying said pressure liquid, said master cylinder and modulating valve having fluid connection with said chamber.

7. In combination, a device to be moved, manual means for controlling the position of the same, a

master cylinder operated by the manual means,-l

a modulating valve means having opposed cylinders and valve plungers therein adapted to control the delivery of pressure liquid from the valve, power cylinders and opposed pistons therein oper- 13 ated by said pressure liquid, a casing having a chamber between said power cylinders and on which casing the power cylinders are mounted, said power pistons being connected to said device, a pump in said chamber having a pressure accumulator connected thereto for supplying said pressure liquid, and a source of compressed air for operating said `pump, said master cylinder, accumulator and modulating valve cylinders having iluid connection with said chamber.

8. In combination, a device to be moved, manual means for controlling the position of the same, a master cylinder operated by the manual means, a modulating valve adapted to control the delivery oi pressure liquid from the valve, power cylinders and opposed pistons therein operated by said pressure liquid, a casing having a chamber -between said power cylinders, said power pistons being connected to said device, a pump in said chamber having a pressure accumulator connected thereto for supplying said pressure liquid, a source of compressed air for operating said pump, and a valve operated by the accumulator for cutting oi the compressed air from the pump, said master cylinder, accumulator and the modulating valve having fluid connection with said chamber.

9. In combination, a device to be moved, a unitary compact power unit comprising manual means for controlling the position of the device, opposed master cylinders, having pistons, operated by the manual means, a modulating valve means having opposed cylinders and valve plungers therein adapted to provide for the controlled delivery of pressure liquid from the valve, power cylinders and opposed pistons therein operated by said pressure liquid, a casing having a chamber between said power cylinders and connected to the valve cylinders and on which' casing the power cylinders are mounted, said power pistonsl being connected to said device, and a pump in said chamber having a pressure accumulator connected thereto for supplying said pressure liquid, said master cylinders, modulating valve cylinders. power cylinders and accumulator being arranged so as to open into said chamber.

1d. In combination, a power unit and a master cylinder controlling means therefor, said unit comprising a hydraulic power creating device with an inlet having an intermittently operating pump, a hydraulic motor, having cylinders and pistons, operated ,by said hydraulic power and connected to a device to be moved thereby, a valve means, fluid actuated'valve operating means connected to the valve means, passage means connecting the valve operating means to the master cylinder controlling means for controlling the application of said hydraulic power to the motor, means, comprising cylinders in hydraulic communication with said inlet, at least at times, of said hydraulic power creating device and double opposed pistons connected to said rst mentioned pistons and said device to be moved so as to move coordinately to motor, adapted to coordinate the travel of said controlling means and the device moved by the pressure from said pump, and a casing having a between said cylinders and' pistons and on hich casing the motor cylinders are mounted, saleA chamber being connected to the pump, said pump being located in said chamber, said motor having a cylinder communicating with said chamber and said valve means having a uid connection to said chamber.

11. In combination, a power unit and a master cylinder controlling means therefor, said unit comprising a hydraulic power creating device li I4 having an inlet, a hydraulic motor, having oppositely acting pressure-receiving elements, operated by said hydraulic power and connected to a device to be moved thereby, a valve means, having two valves, uid actuated valve operating means connected to the valve means, passage means connecting the valve operating means to the master cylinder controlling means for controlling the application of said hydraulic power to each of said elements, respectively, of the motor, means, comprising cylinders in hydraulic communication with said hydraulic power creating device and double opposed pistons connected to said elements and connected to said device to be moved so as to move coordinately to said motor, adapted to coordinate the travel of said controlling means and the device to be moved, and a casing, having a chamber between said pistons and on which casing the motor cylinders are mounted, said chamber being connected to said inlet, said hydraulic power creating device being associated with said chamber and said motor having cylinders communicating with said chamber.

l2. `In combination, a power unit and a master cylinder controlling means therefor, said unit comprising a hydraulic power creating device having an inlet, a hydraulic reciprocating motor, having oppositely acting pressure-receiving elements, operated by said hydraulic power and connected to a device to be moved thereby, a valve means, having two valves, fluid actuated valve operating means connected to the valve means.

passage means connecting the valve operating means to the master cylinder controlling means for controlling. the application of said hydraulic power to each of said elements, respectively, of the motor, means, comprising cylinders connected to said passages and in hydraulic communication with said hydraulic power creating device and double opposed pistons connected to said elements receiving elements being in communication with` said chamber. A

13. ln communication, a power unit and a master cylinder controlling means therefor, said unit comprising a hydraulic power creating device having an inlet, a hydraulic motor, having oppositely acting pressure-receiving elements, operated by said hydraulic power and connected to a device to 'be moved thereby, a plunger-operated valve means, having two valves having check valved inlets to prevent reversibility, fluid actuated valve operating means connected to the valve means, passage means connecting the valve operating means to the master cylinder controlling means for controlling the application of said hydraulic power to each of said elements, respectively, of the motor, means, comprising cylinders connected to said passages and in hydraulic communication with said hydraulic power creating device and double opposed pistons connected to said elements and connected to said device to be. moved so as to move coordinately to said motor, adapted to coordinate the travel of said controlling means and the device to be moved, and a casing having a chamber between said pistons and on which casing 15 the motor cylinders are mounted, said chamber being connected to said inlet, said hydraulic power creating device being associated with said chamber and said pressure-receiving elements being in communicationwith said chamber.

14. In combination, a power unit and a master cylinder controlling means therefor, said unit comprising a hydraulic power creating device having an inlet, a hydraulic motor, having oppositely acting pressure-receiving elements, operpistons connected to said elements and connected to said device to be moved so as to move coordinately to said motor, adapted to coordinate the travel of said controlling means and the device to be moved, and a casing having a chamber between said pistons and on which casing the motor cylinders are mounted, said chamber being connected to said inlet, said hydraulic power creating device being associated with said chamber and said pressure-receiving elements 7being in communication with said chamber.

15. In combination, a casing, a source of fluid pressure, work performing pistons, a valve mechanism for controlling the supply of iluid pressure thereto, cylinders for said work performing pistons mounted on opposite sides of the casing into which casing the cylinders open, the pistons having a connection through the inside of the casing, master cylinders for operating the valve mechanism, having opposed pistons connected together in said casing into which the master cylinders open. and a pump for producing said pressure, said pump being located in said casing having a pump inlet to draw liquid from within the casing,.the,casing having exhaust connections leading into the casing from said valve mechanism.

16. In combination, a casing, a source of fluid pressure, work performing pistons, a valve mechassenso anism for controlling the supply of fluid pressure thereto, cylinders for said work performing pistons mounted on the casing into which the cylinders open, the pistons having a connection through the inside of the casing', master cylinders opening into the inside oi the casing for operating the valve mechanism, a pump for producing said pressure, said pump being located in the inside of said casing, the casing having exhaust connections leading from said valve mechanism to the inside of the casing, a cover plate for coveringthe interior ofthe casing, to which cover plate the pump is connected on the inside of said casing, the pump being located on the inside of the casing, and an air motor and pressure controller for the pump, the air motor lbeing mounted on the outside o! the cover plate.

EDWARD A. ROCKWELL.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS vNumber Name Date 752,491 Warren Feb. 16, 1904 897,907 Lang Sept. 8, 1908 1,147,436 Ragonnet July 20, 1915 1,299,284 Baader Apr. l, 1919 1,318,732 De Havilland et al. Oct. 14, 1919 1,675,576 Roberts July 3, 1928 1,855,386 Doolittle Apr. 26, 1932 1,960,996 Guernsey May 29, 1934 1,962,857 Cash June 12, 1934 1,976,129 Johnson Oct. 9, 1934 2,136,638. Rockwell Nov. 15, 1938 2,197,772 Rockwell Apr. 23, 1940 2,236,467 Clench Mar. 25, 1941 2,239,566 Mercier Apr. 22, 1941 2,239,893 Jackman Apr. 29, 1941 2,252,660 Kulikoti Aug. 12, 1941 2,261,444 Neubert Nov. 4, 1941 2,264,675 Nardoe Dec. 2, 1941 2,276,418 Rockwell Mar. 17, 1942 2,282,652 Henning May 12, 1942 2,349,295 Napier May 23, 1944 FOREIGN PATENTSl Number Country Date 374,583. Great Britain -..June 16, 1932 

